Arresting hook



, Nov. 2, 194s. y

F.` N. DICKERMAN 2,452,911

ARRESTING Hooxv Filed Jan. 8,1946

2 Shees-Sheet 1 Nov. 2, 4194s.

" Filed Jan. 8, `1946 F. N. DICKERMAN 2,452,911 l ARRESTING Hoox 2 sheets-sheet 2 Patented Nov. 2, 1948 Fred N. Dickerman,

Nichols, Conn., assignor to2 `United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application January 8, 1946, Serial No. 639,887

My invention relates to hooks for arresting the motion of airplanes and specically to an arresting hook adapted to be stowed in the top of atail cone housing when in its inoperative position; A hook stowed in this manner is particularly adapted to use in V-tail airplanes but obviously is not entirely limited to such use.

One object of my invention is to 4provide a simple pivoting device to supplant the conventional, me-

chanically complex, and heavy track mechanism normally used to eiectrelease and retraction of arresting hooks.

Afurther `object is to provide an arresting rhook housed in the top of the plane structure rather than in the bottom thus doing away with the danger of hooks dropping and catching obstructions during take-'ods or landings on shore stations. Such dropping of hooks during take-offs over areas equipped with arresting gear generally causes the engagement of the arresting gear by the arresting hook and stoppage of the .plane with possible injury to personnel and/or equipment.

Further advantages accomplished by this invention are in the provision of a simple means of s-toring the arresting hook in an inoperative position in an automatically closable recess provided for .the purpose and in the provision of a high point of attachment for the arresting hook, thus reducing the undesirable characteristic of tail rise ordinar ily .present in conventional arresting hook installations.' i

Still further advantages willI appear from time to time throughout the specication and claims.

It is to be understood that the form of this invention, herewith shown and described, is to be taken as a preferred example vof the earn-e, and

that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of this invention, or the scope of the subjoined claims.

Referring to the drawings:

Figure l is a plan view with the tail cone removed and showing the structure as it appears with the hook in the inoperative position and with the 'hook itself broken away to better show the relation of the parts.

Figure 2 is a side elevational view Itaken along the line 2 2 of Figure 1 but showing in addition the entire hook, the enclosing door and the door operating means. p

Figure `3 is a schematic representation of the operation of the hydraulic retracting strut.

Figure 4 is a view similar to Figure 2 but showlng the hook in operative position. Y.

`Figure 5 is a section along the line 5-5 of Figure 4 and particularly shows :the door operating means and the means for securing the entire tail and hook structure to the fuselage.

Figure 6 is a rear view of an airplane tail struc- 8 Claims. (Cl. 244-110) ture showing my invention in its operative position.

Like parts are indicated by like characters throughout the specication and drawings.

The tail cone I El has its forwardlbulkhead I 4 secured to th-e after fuselage bulkhead 8 yby means of bolts as shown in Figure 5. The hook I2 is keyed to ring gear 3 which -is pivoted on a transverse axis I 3 mounted at the convergent extremitics of' four structural supporting members 9 which have their forward ends bolted to the aft side of bulkhead I4. Mounted on transverse axis I5, forward of gear 3, and so as to be in engaging relationship therewith is a gear sector which functions to rotate gear 3, thus raising and lowering the hook I2. Pivoted at its forward end to bulkhead lf3 and at its aft end to an arm protruding from gear sector 4 is ya conventional damping strut 2 containing a dashpot arrangement, to dampen .the bounce of lthe hook I2, and a heavily compressed spring 20 for expansion of the two parts. In the embodiment shown, the chamber Il for loading the strut is placed off center, as best shown in Figure 1, to allow unobstructed movement of the parts of my invention.

To provide gear sector 4 with initial movement, the design includes a hydraulicretracting strut. This strut comprises lthe actuating cylinder which contains the piston I 8. The piston rod of piston 3 has concentric therewith a freely moving sleeve It, the aft extremity of which is fired to a point on the periphery of the gear sector A. -The forward end of the actuating cylinder is pivoteld to `bulkhead I4. Inlet ports i9 are provided for connection with the hydraulic system of the airplane in the :conventional manner.

The construction further includes at l a sponge rubber pad 4beneath. the hook in stowed positie-nto prevent rattling and t-o keep the hook snug, In

. the top surface of the easily removable tail cone IB is a hinged door 5 possessing a protruding linkage E which closes the door upon stowing the hook by reason of engagement of the hook shank with the door linkage. The door ls opened by the hook shank. Linkage E is spring-loaded so as to keep the door in an open position until the hook pulls it closed. Y

Figure 3 represents, schematically, various positions of the parts of the hydraulic retracting strut for the various conditions incident to the operation of my invention. When the hook is in stowed position, the hydraulic retracting strut is in` the position indicated in the top sketch. of vFigure 3, the piston being retracted inthe cylinder and the sleeve I5 being in its forwardmost position, as seen in Figures land 2. As hydraulic pressure is applied against the piston head by admission of hydraulic flu-id into the forward chamber of the cylinder, the piston rod carrying the sleeve with it extends .to the position shown inthe Aside of the sector center, -at which time the coinpr-essed springen the damping strut expands, lowering the hook to its deck engaging position. This motion carries the sleeve It on the piston rod oi` the actuating -cylinder to the position shown in the third sketch and as can be seen in Figure 4. Pressure of spring 2d keeps the arresting hook down in engaging position but bouncing of; the hook would result in the sleeve i6 assumir g some intermediate position such as lthat shown in the fourth sketch. rEhe hook is placed in its stowed position by the obvious means, as indicated in the fifth sketch of Figure 3, of admitting hydraulic uid to the opposite chamber of the hydraulic retracting strut, causing the piston rod to retract in the cylinder and carrying sleeve IS with it, which motion rotates the gear sector 4 clockwise, causing gear 3 to which the hook is keyed to rotate counter-clockwise. As the hook reaches its fully stowed position, it engages the linkage on door 5 and clos-es that door behind it, b-eing locked in stowed position by the damping strut 2 which has again rotated past the center point of gear sector 4.

From the foregoing it will be app-arent that a simpl-e, pivotally acting arresting hook is provided and one which is housed in the top of the tail icone structure. rThis arrangement provides added safety and simplicity -of operation.

What I claim is:

1. An arresting hook mechanism for airplanes comprising a frame member adapted to be atu tached to an airplane, a ring gear, supporting means interposed between said frame member and said ring gears an arresting hook keyed to said ring gear, a gear sector in engagement with said ring gear, and means to rotate said gear sector thereby Causing pivotal movement of said arresting hook.

2. An arresting hook mechanism for airplanes comprising a frame member adapted to be attached to an airplane, a ring gear, supporting means interposed between said frame member and said ring gear, an arresting hook keyed to said ring gear, a gear sector in engagement with said ring gear, and means to rotate said gear sector thereby causing pivotal movement of said arresting hook, said means comprising a hydraulic actuating strut pivotally attached to said frame member and to said gear sector.

3. An arresting hook mechanism for airplanes comprising a frame member adapted to be attached to an airplane, a ring gear, supportingl means interposed between said frame member and said ring gear, an arresting hook keyed to said ring gear, a gear sector in engagement with said ring gear, a hydraulic actuating strut pivotally attached to said frame member and to said gear sector, and means for damping movement of said arresting hook.

4. An arresting hook mechanism for airplanes comprising a frame member adaptedto be attached to an airplane, a ring gear, supporting means interposed between said frame member and said ring gear, an arresting hook keyed to said ring gear, a gear' sector in engagement, with said ring gear, a hydraulic actuating strut pivotally Vattached to said frame member and to said gear sector, and a damping strut, saidv damping strut comprising a piston pivotally attached to said frame member, a cylinder member attached to said gear sector, and a spring so placed around said piston as to be compressed; by movement of said piston.

5. An arresting hookmechanism for airplanes comprising a frame member adapted to be attached to an airplane, a ring gear, supporting means interposed between said frame member and said ring gear,d an arresting hook keyed to said ring gear, a, gear sector in engagement with said ring' gear, an extension arm on said gear sector,l a hydraulic actuating strut pivotally attached to the vperiphery of said gear sector andl to said frame member and a damping strut pivotally attached to said extension arm and to said frame member and adapted to lock said, arresting hook in each, of. its limiting positions, and to,

dampen movementA of said hook due. to bouncing.

6. A tail. cone adapted to be attached' to an airplane, an elongated opening in the top of said tail cone, an arresting hook pivotally. mounted in said tail cone and means to cause pivotal motion of said arresting hook through said elongated opening and into operative and stowed positions.,

7. A tail cone adapted to be attached to an airplane, an elongated opening in the top of-- said, tail cone, a door hinged to said tail cone and adapted to closev said elongated opening, an arresting hook pivotally mountedV in said tail cone means to cause pivotal motion of said arresting hook through said elongated opening and into. operative and stowed positions andv cooperating means on saidtail. cone and on said. door adapted to open said doorv when said arresting hook is caused to move out of` saidI tailA cone and to close said door when said arresting hook is caused to move into said tail cone.

8. ,An arresting hook mechanism for airplanes comprising a frame member adapted to be attached to an airplane, a ring gear, supporting means interposed between said frame member and said ring gear, an arresting hook keyed to said ring gear, a gear sector in engagement with said ring gear, an extension arm on saidgear sector, a lidded compartment insetV in the upper surface. of said airplane, spring-loaded means connected to the lid of the said compartment for openingA and closingv said` lid uponV the release-and stowage of said arresting hook, a hydraulically actuated strut pivotally-attached to the periphery of said gear sector and to said frame member,

partment and on the other side to hold said ar-.

resting hook in operative position.

FRED N. DICKERMAN.

REFERENCES Ci'lED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Y Date 1,743,393 Reid Jan. 14, 1930 1,893,591 Minshall fr Jan, 10,1933, 2,117,786 Blume* ,.M May 17, 1938 2,189,094 

